Multiple-piezo-electric-crystal holder



Dec. 7 1926. 1,609,744

. A. M. TROGNER MULTIPLE PIEZO ELECTRIC CRYSTAL HOLDER Filed June 4, 1926 2 sheets-sheet 1 INVENIOR. Ari/mrflfigmr,

BY 4 V ATTORNEY A. M. TROGNER MULTIPLE PIEZO ELECTRIC CRYSTAL HOLDER Filed June 4, 1926 2 Sheets-Sheet 2 Yam 2 INVENTOR.

A mfj v ATTORNEY Patented Dec. 1,1926;

ARTHUR H. TBOGNEB, 0F TAKOMA PARK, MARYLAND.

I EULTIPLE-PIEZO-ELECTRIG-CRYSTAL HOLDER.

Application am June 4,

My invention relates broadly to frequency control apparatus and more particularly to a mounting for a plurality of piezo electric crystal devices used in the control of h gh frequency circuits at different frequencles.

One of the objects of my inventlon is to provide a practical construction of piezo electric crystal holder which may be mounted to rotate 1n coordination with rotary control switches for adjusting the electrical constants of a circuit simultaneously with the connection of a particular crystal in the frequency control circuit with which the apparatus is arranged to cooperate. v

- Another object of m invention 1s to provide a. rotary iezo e ectric crystal holder having a lura 'ty"of piezo electric crystal devices different frequency characteris. tics wherein the piezo electric crystal de-.

vices may be mounted upon the holder in such manner that free mechanical vibration may take place with substantially norestriction with respect to the mechanical form) of mounting for the piezo electric crystal devices.

Another object of my invention 15 to pro vide a rotary construction of plezo electric crystal holder which may be maintained at a uniform temperature independent of heat which may be inherently generated from the rapid mechanical vibration of selected piezo electrical devices supported by the mounting. I a e Other and further objects of my invention will be understood from the specification hereinaften following by reference to the accompanying drawings wherein: Fig. 1 is a perspective view partially broken away showing the construction of the rotary piezo electric crystal'holder of my invention; Fig. 2 is a cross-sectional -view taken through the rotary Igpiezo electric crystal holder of Fig. 1; g. 3 is a cross-sectional view of a modified form of piezo electric crystal holder having means for mount-mg choke coil units in association with each of the several piezo electric crystal holders in radial position; and Fig, 4:- is a where facilities must be fragmentary cross-sectional view showing a system for cooling the rotary piezo electric crystal holder.

- In the, operation of radio transmitters instantaneous change in t e apparatus for transmission on different wave lengths, I

rovided for the 1926. Serial No. 113,791.

have found that a particular construction of piezo electric crystal holder must be provided in order to coordinate the frequency control system with the switching apparatus which is arranged to control the wave length range of the transmitter. In certain. transmitters which must handle traific with various stations while communication is being simultaneously conducted by and between adjacent stations, it is necessary for the operators at the stations desirin to establish a communication channel to se ect a frequency band which is not busy. The shifting of the circuits at the transmitter to the selected frequency band must be efl'ected' without loss of time. The change in the adjustment of wave changer switches'which control the inductance or capacity-elements of the transmitter circuits must be coordinated with a similar shift in the frequency control circuit where a selected piezo electric crystal device must be connected in the frequency control circuit.

I have developed holder as descri ed herein for the purpose of permitting a rapid selection of a piezo electric crystal of a predetermined freuency for connecting such crystal in the reqllliency control circuit. The construction of t e rotary piezo electric crystal holder is relatively simple and Inexpensive and special provision is made for maintaining the piezo electric crystal holder at a uniform temperature. Each piezo electric crystal is mounted on the'periphery of the rotary holder in such manner that free mechanical vibration of the crystal may take place without restriction and the maximum current a piezo electric crystal for sustaining oscillations 11mm associated electron tube oscillator circuit thereby obtained angles to the radially extending portion 1. g The portion 4 is in the nature of a cylindrical drum the outer surface of which is provided with a multiplicity of flat areas .5 each of which supports a piezo electric crystal of a particular frequency characteristic.

As many ofthe flat areas as there are frequency channels to be covered may be provided. The flat areas are apertured as represented at 6 for the passage of loops of cord or'thread 7 and 8 therethrough for the purpose of locating the piezo electric crysta device and an upper contact plate with respect to the fiat area portions. The cords 7 and 8 are stretched taut by means of a cantilever spring device 9 secured in the pocket portions 10 formed in the rear wall 11 of the piezo electric crystal holder. A hook portion 12 is provided on the resilient spring device 9 in order to secure the loops of cord 7 and 8 in a position centrally over the upper contact plate 14 of the complete assembly. A flexible lead 13 extends from the upper contact plate 14 connec'tin to binding posts 16 on the rear of the inslilated panel 11 estab lishing connection through the upper contact plate 14 with the upper surface of the piezo electric crystal 15 which is mounted in position on the fiat surface 5. Each of the binding posts 16 terminates in a blade portion 17 which will readily slide between the jaws of a contact clip 18 during the rotation of the piezo electric crystal holder in order to establish connection with any selected piezo electric crystal devices.

A housing is provided around the piezo electric crystal devices as represented at 28 and 30 forming a base like annular enclosure for the multiplicity of piezo electric crystal devices which are supported around the periphery of the metallic drum. In order to maintain the temperature of the piezo electric crystal holder and the piezo electric crystal thereon at a uniform value, I may provide a water jacket 31 adjacent the surface 1. The water jacketis provided with a fluid inlet 32 and a fluid outlet 33 so that cooling water may be applied in good thermal c011- tact with the flange portion of the rotary piezo electric crystal holder for removing the heat generated during the operation of the piezo electric crystal by a process of conduction. It will also be understood that by the circulation of cooling water through thewater jacket the piezo electric crystal may be maintained at a temperature above the surrounding tem rature which is often desirable for securing maximum eflieiency in operation.

In Fig. 3 I have shown a modified construction of a rotary piezo electric crystal holder which-is constructed of insulated material 26 and 27 with metallic contact plates '20 mounted around the surface of the insulated'drum 27 for the support of the piezo electric crystal device 15. ashereinbefore described. Each of the plates 20 is provided with a depending post 21 terminating "in a clip 22. The inner portion of the rotary ho der may be, provided with clip members 21 secured as represented at 25 by a post which grounds to the metallic shaft 2. Between the cli members 22 I insert a choke coil 23 individual to each of the frequency control circuits. It will be observed that the choke coils 23 are readily positioned within the rotary piezo electric crystal holder in the manner of the spokes of a wheel thereby greatly conservin space and at the same time providing inc ividual piezo electric crystal devices with choke coils in series therewith for instantaneous connection in the frequency control circuit of a transmitting system in coordination with the change of electrical constants of the circuits with which the piezo electric crystal apparatus is associated.

I have found the construction of the rotary piezo electric crystal holder as described herein to be very satisfactory as it rmits a rapid connection of the piezo electric crystal device in the frequency control circuit and yet eliminates the possibility which is always present when a large number of separate piezo electric crystal holders are provided for plug in connection, of misplacing one or more crystals in a' set and kee s the crystals positively arranged in a prec etermined sequence. The fact-that the several piezo electric crystal devices are compactly arranged enables the rotar holder to serve as its own crystal selector thus avoiding the complication of associated switch mechanism.

While I have described my invention in one of its preferred embodiments, I desire that it be understood that modifications may be made without departing from the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. Piezo electric crystal apparatus comprising a rotary drum, a shaft. member mounted to rotate with said drum, said drum being provided with a plurality of flattened surfaces ,upon its periphery, piezo electric crystals of different frequency characteris tics carried by said flattened surfaces, a contact plate for establishing connection with the upper surface of each of the said piezo electric crystals, spring devices. arranged around said drum for maintaining said piezo electric crystals and said contact plate in position with respect to each other, and

.means for establishing connection with a \selected one of said piezo electric crystals by rotating said drum.

2. A holder for a multiplicity of piezo electric crystals of differing frequency characteristics comprising a metallic drum flattened at a plurality of points around its periphery, piezo electric crystal devices positioned on each of the flattened portions of said drum, means for establishing connection with the upper surface of each of said piezo electric crystals, and a shaft member for r0- locate sai tating said drum for establishin electrical connection with a selected one 0 said piezo electric crystal devices to the exclusion of others of said devices.

3. Piezo electric crystal apparatus comprising in combination a rotary drum, a plurality of-v flattened metallic surfaces on the peri hery of said drum, each of said flattene surfaces providing means for 225120 ing a piezo electric crystal of sale frequency characteristic, an individual contact plate for establishin connection with the uppersurface of eac of said piezo electric crystal and terminal connections for each of said piezo electric crystals whereby said drum may be rotated to brin a selected one of said terminal connections into association with a frequency control circuit. 4. Piezo electric crystal apparatus comprising a rotatable drum, a plurality of flattenedsurfaces on the rlphery of said drum for supporting indivi ual iezo electric crysquency characv tal elements of 'difiering' teristic, an upper contact plate for each of said piezo electric crystal elements, an insulated annular wall adjacent the periphery of said drum, aplur'ality of cantilever ring devices extendin from said wall an terminating centra y of each of said flattened surfaces, flexible cord members looped through said surfaces'and stretched taut by said sprin devices said cords serving to piezo electric crystal elements and said upper contact plates with respect to each of said flattened surfaces, and means for efiectively utilizing selected piezo electric crystal elements in a frequency control circuit.

Piezo electric crystal apparatus comprising a rotary shaft, a drum carried by said shaft, an annular housing supported upon the periphery of said drum, said drum having a plurality of flattened surfaces for supporting a corresponding number of piezo electric crystal elements within said annular housing and terminals carried by said annular housing for each of said piezo electric crystal elements whereby rotation of said drgim effects the connection of a selected of flattened surfaces on said cylin rical peripheral rtion for supporting a lurahty of piezo e ectric crystal slements ea having a predetermined frequency characteristic, an upper contact plate individualto eachof said piezo electric crystal elements, means for locating said upper contact plates in position upon each of said piezo electric crystal elements and a fluid circulating system in thermal contact with said radially extending web portion for maintainin said flattened surfaces at a substantia y uniform temperature by a process of heat conduction.

7. liezo electric crystal apparatus com-- prising in combination a wheel-like structure carried by a rotatable shaft member, a pluralit carried y the periphery of said wheel-like structure and a pluralit of choke coils -ra.- dially positioned with1n said wheel-like structure and individual to each of said of piezo electric crystal devices piezo electric crystal devices, said wheel-like structure .bein rotatable to select a particular one of sai iezo electric crystal devices and associated c oke coils for controlling an electrical circuit.

8f Piezo electric crystal apparatus comprising in combinationa rotatable drum, an annular housin carried adjacent the periphery of said rum, a multiplicity of piei'o electric crystal "elements of diifering frequency characteristics 'positionedwithin said housing and choke coildevices con-- nected with each of said piezo electric crystal elements and radially positioned withim said drum, terminals individual to each of said piezo electric crystal elements carried said annular housing for efiectively inb ch iding a selected piezo electric crystal de-f vice and associated choke coil in an electrical circuit upon rotation of said drum,

7 ARTHUR M. TROGNER.

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